Electrodeposited CuSbTe thin films with enhanced thermoelectric performance

Abstract

Antimony telluride (Sb₂Te₃) based alloys are well known as promising thermoelectric materials for near-room temperature applications. In this work, we present a simple and cost effective electrodeposition approach for developing CuSbTe films with enhanced thermoelectric characteristics. Amorphous CuSbTe solid solutions of varied compositions are electrodeposited by adjusting the [Cu²⁺] concentration in the electrolytes. The increasing copper content in the films resulted in a crystalline to amorphous phase transition. This Cu-induced phase transition creates anti-site defects, resulting in lower carrier concentration, increased Hall mobility, and a higher Seebeck coefficient. The CuSbTe film with 5.7 at% Cu has an extraordinarily high power factor of 2.8 mW m⁻¹ K⁻², which originates from a high Seebeck coefficient of −382 μV K⁻¹ and a good electrical conductivity of 2.05 × 10⁴ S m⁻¹. To demonstrate the feasibility of applying this material as an n-type leg, the film is electrodeposited onto flexible Nylon cloth and validated for device fabrication. By delivering a maximum power output of 120 nW for a temperature difference of 30 K, our flexible device confirmed the prospective of this material in flexible thermoelectric device applications.